Biomolecules (Updated 2023) — Transcript

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1. 0:04I want you to think for a moment  about your very favorite food. What
2. 0:07is it? We all have different food preferences,
3. 0:09but food is a source of large molecules that  are needed for life called biomolecules. Also
4. 0:15known as macromolecules. Carbohydrates,  Lipids, Proteins, and Nucleic Acids.
5. 0:21In different types of food, you might find higher  amounts of these biomolecules. For example,
6. 0:26peanut butter can be high in both proteins and  lipids. And while we’ll mention examples of
7. 0:31foods that contain different biomolecules in this  video, this is not a video on nutrition – this is
8. 0:36a video on the classes of biomolecules and their  importance to the structure and function of cells.
9. 0:41And, therefore, also to the entire organism  because organisms consist of these cells.
10. 0:46Before we get into details  about the 4 biomolecules,
11. 0:48we need to talk about one very important vocabulary word. The word monomer. A monomer is a building
12. 0:54block. If I had some large substance, the  parts that make up that substance are called
13. 0:59monomers. With each biomolecule class, we  will mention its monomer if it applies.
14. 1:04We’ll start with the biomolecule  class of carbohydrates. Generally,
15. 1:08food sources such as bread, pasta, fruit, and  vegetables tend to be high in carbohydrates.
16. 1:13The monomer of a carbohydrate (remember:  that means the building block) is the
17. 1:18monosaccharide. One example of a monosaccharide  is the sugar glucose. Glucose is a pretty
18. 1:24big deal considering it’s used in cellular  respiration to make ATP, an energy currency.
19. 1:29If two monosaccharides – such as glucose - are  combined, you get a disaccharide. For example,
20. 1:37put these two glucose sugars together, and  you get the disaccharide maltose. By the way,
21. 1:42a lot of sugars have that -ose ending.  Glucose, maltose, lactose, sucrose,
22. 1:48fructose. I could go on. The ending -ose can  be a carbohydrate clue. If you join a lot of
23. 1:55monosaccharides together, that can combine  to make a polysaccharide. A big carbohydrate.
24. 2:01So how are carbohydrates important to an organism  and the structure and function of its cells? Well,
25. 2:07plants have cell walls of carbohydrates,  specifically a large one known as cellulose.
26. 2:12Fungi have cell walls of carbohydrates too,  specifically one known as chitin. Fun Fact:
27. 2:18that carbohydrate chitin is also what  makes up the exoskeleton of insects.
28. 2:23We mentioned glucose is used to make  ATP. That makes carbohydrates a fast
29. 2:28source of energy for cells. So that’s a big  function for carbs: a major energy source
30. 2:33that cells can access. That energy can also be  stored in a polysaccharide form ---remember,
31. 2:38polysaccharide is a big carbohydrate---such  as starch for plants or glycogen for animals.
32. 2:44Next up: lipids. Lipids include fats and oils;  examples of food sources could include butter
33. 2:50or olive oil. This is a seriously diverse  group. Meaning there are a lot of types of
34. 2:55lipids. There are triglycerides. There  are phospholipids. There are steroids.
35. 3:00These are just some examples. Most – but  not all - lipids have building blocks of
36. 3:05glycerol and fatty acids. One thing though  that lipids generally share? Generally,
37. 3:10they’re hydrophobic or at least contain  a significant hydrophobic component. That
38. 3:14means lipids, or at least a major component of  them, don’t like water. Lipids generally won’t
39. 3:19dissolve in water. And that’s interesting,  as generally, the other biomolecules will.
40. 3:23So how are lipids important to an organism and the  structure and function of its cells? Remember how
41. 3:29we said all cells – plant cells, animal cells,  all cells – have membranes? Well thank you,
42. 3:34phospholipids, for that phospholipid  bilayer, because that’s right,
43. 3:37lipids make up cell membrane structure.  Lipids have a major function of being a
44. 3:42source of long-term energy storage. You  remember how we said carbohydrates were a
45. 3:47fast source of energy but when those carbs are  used up, lipids have a function as long-term
46. 3:52energy storage that an organism can use. Lipids  also are very important for different types of
47. 3:57insulation. The insulation may involve helping  a cell carry an electrical impulse: for example,
48. 4:03this myelin sheath made of lipids that can be  found on many neurons. Or the insulation may
49. 4:08involve temperature regulation so thermal  insulation: for example, the blubber on
50. 4:13this adult harp seal is made of lipids, helping it  conserve heat. Another cool function about lipids:
51. 4:18many lipids act as hormones which are chemical  messengers for many different processes.
52. 4:23Next up: proteins! Protein food sources include  beans, meat, nuts, and eggs. The monomer of
53. 4:30a protein is an amino acid. Usually, proteins  consist of many amino acids bonded together.
54. 4:36There are different types of amino acids. So  how are proteins important to an organism and
55. 4:41the structure and function of its cells?  Structure wise, tissue like muscle tissue,
56. 4:45consists heavily of proteins. Proteins can  make up all kinds of other structures – hair
57. 4:51or collagen - for example. Proteins can also  be found embedded in cell membranes as protein
58. 4:56channels and channels are important to that cell  membrane structure with functions of letting
59. 5:01certain substances pass through. Proteins  can also be receptors which are critical in
60. 5:05cell signaling so cells can coordinate actions  together. Most enzymes are made of proteins.
61. 5:10Remember enzymes can build up or break down  substances in all kinds of metabolic processes.
62. 5:16Antibodies – which are made by immune cells in  your body – are proteins and they are involved
63. 5:22in protecting your body. And some critical  hormones such as insulin are proteins. And when
64. 5:27we start talking about genes – genes are made  of DNA – but many genes do code for proteins.
65. 5:34And that brings us to our last one that includes  DNA: nucleic acids. Nucleic acids include DNA and
66. 5:41RNA, which we'll get to in more depth when we  get to genetics. Nucleic acids have a monomer
67. 5:46called a nucleotide. That's going to be an easy  one for you to remember because nucleotide sounds
68. 5:51like nucleic acid. By the way, you might wonder:  are nucleic acids like DNA and RNA found in my
69. 5:58food? And the answer would be yes! Whenever you  eat something that came from something living,
70. 6:02it actually could still have DNA inside  it. For example, when you eat a strawberry,
71. 6:07you're actually crunching all the cells that  made up that strawberry. In the nucleus of
72. 6:11all of those strawberry cells is DNA. Any type  of life - like plants or animals or fungi or
73. 6:18bacteria - they must contain nucleic acids  like DNA to direct the cells' activities.
74. 6:22How are nucleic acids important for your  cells? Well, most of your cells contain
75. 6:28all of your genetic information in the form  of nucleic acids -DNA and RNA- and this is
76. 6:32needed for the coding of your traits. Traits  involved in structure and various functions.
77. 6:37Ok, so we just did a very general  tour of 4 biomolecules. Before we go,
78. 6:42I just have to marvel at biomolecule  structure. Because...it’s absolutely
79. 6:47beautiful. So if I arrange them in the order we  did: carbs, lipids, proteins, and nucleic acids,
80. 6:53how might we remember the major and most  common elements in them? There’s a popular
81. 6:58mnemonic known as CHO, CHO, CHON, CHONP  – although it’s “chomp” with an “n” - to
82. 7:04help remember the C for carbon, H for hydrogen,  O for oxygen, N for nitrogen, and P for phosphorous.
83. 7:11Does that mean you won’t find other elements  in the biomolecules? Of course not! But it’s
84. 7:15important to understand the arrangement  of these elements in biomolecules,
85. 7:18because the structure of the arrangement  greatly impacts their function. You can
86. 7:23learn more in our further reading  suggestions in the description. Well,
87. 7:27that’s it for the Amoeba Sisters,  and we remind you to stay curious.